Background In utero or early life exposure to aflatoxin, which contaminates staple crops in disadvantaged settings, may compromise pregnancy and infant outcomes, but investigations into the extent, persistence, and determinants of aflatoxin exposure at these life stages have lacked longitudinal data collection and broad geographic representation. Objectives Aflatoxin exposure and selected determinants thereof were characterized in mother-child dyads with serial plasma/serum samples in prenatal, perinatal, and early life in Malawi and Bangladesh. Methods Circulating aflatoxin B1 (AFB1)-lysine albumin adducts were measured in dyads from Bangladesh (n = 573; maternal 1st and 3rd trimester, 3 months postpartum, cord blood, infant 24 months) and Malawi (n = 255; maternal 2nd and 3rd trimester, 6 months postpartum, infant 6 and 18 months) with isotope dilution mass spectrometry. We examined AFB1-lysine adduct magnitude, persistence, seasonality, associations with infant feeding, and estimated daily AFB1 intake. Results Maternal AFB1-lysine was higher in Malawi (98% detectable; median, IQR: 0.469, 0.225–1.027 pg/µL) than Bangladesh (59%; 0.030, non-detectable (nd)–0.077 pg/µL). Whereas estimated dietary exposure in Malawi was temporally stable (648 ng AFB1/day), estimated intake in Bangladesh was reduced 94% between rainy and winter seasons (98 to 6 ng/day). AFB1-lysine was low in cord blood from Bangladesh (15% detectable; 0.045, 0.031–0.088 among detectable) and in Malawian infants at 6 months of age (0.072, nd–0.236), but reached maternal levels by 18 or 24 months (Bangladesh: 0.034, nd–0.063; Malawi: 0.370, 0.195–0.964). In Malawian infants, exclusive breastfeeding at 3 months was associated with 58% lower AFB1-lysine levels at 6 months compared to other feeding modes (P = 0.010). Conclusions Among pregnant women, aflatoxin exposure was persistently high in Malawi, while lower and seasonal in Bangladesh. Infants were partially protected from exposure in utero and with exclusive breastfeeding, but exposures reached adult levels by 18–24 months of age. Registered at clinicaltrials.gov: NCT00860470 and NCT01239693.

The assessment of aflatoxin B1 (AFB1) exposure using isotope-dilution liquid chromatography-mass spectrometry (LCMS) of AFB1-lysine adducts in human serum albumin (HSA) has proven to be a highly productive strategy for the biomonitoring of AFB1 exposure. To compare samples across different individuals and settings, the conventional practice has involved the normalization of raw AFB1-lysine adduct concentrations (e.g., pg/mL serum or plasma) to the total circulating HSA concentration (e.g., pg/mg HSA). It is hypothesized that this practice corrects for technical error, between-person variance in HSA synthesis or AFB1 metabolism, and other factors. However, the validity of this hypothesis has been largely unexamined by empirical analysis. The objective of this work was to test the concept that HSA normalization of AFB1-lysine adduct concentrations effectively adjusts for biological and technical variance and improves AFB1 internal dose estimates. Using data from AFB1-lysine and HSA measurements in 763 subjects, in combination with regression and Monte Carlo simulation techniques, we found that HSA accounts for essentially none of the between-person variance in HSA-normalized (R2 = 0.04) or raw AFB1-lysine measurements (R2 = 0.0001), and that HSA normalization of AFB1-lysine levels with empirical HSA values does not reduce measurement error any better than does the use of simulated data (n = 20,000). These findings were robust across diverse populations (Guatemala, China, Chile), AFB1 exposures (105 range), HSA assays (dye-binding and immunoassay), and disease states (healthy, gallstones, and gallbladder cancer). HSA normalization results in arithmetic transformation with the addition of technical error from the measurement of HSA. Combined with the added analysis time, cost, and sample consumption, these results suggest that it may be prudent to abandon the practice of normalizing adducts to HSA concentration when measuring any HSA adducts—not only AFB1-lys adducts—when using LCMS in serum/plasma.

Introduction Chest radiography is a diagnostic tool commonly used by medical providers to assess high-altitude pulmonary edema (HAPE). Although HAPE often causes a pattern of pulmonary edema with right lower lung predominance, previous research has shown that there is no single radiographic finding associated with the condition. The majority of research involves a retrospective analysis of chest radiographs taken at the time of HAPE diagnosis. Little is known about the radiographic progression of HAPE during treatment or medical evacuation. Materials and Methods Three sequential chest radiographs were obtained from two patients diagnosed with HAPE at the Amundsen-Scott South Pole Station, Antarctica, who required treatment and medical evacuation. Deidentified and temporally randomized images were reviewed in a blinded fashion by two radiologists. A score of 0 (normal lung) to 4 (alveolar disease) was assigned for each of the four lung quadrants for an aggregate possible score ranging from 0 to 16 for each radiograph. Results Patient 1’s initial radiograph showed severe HAPE with an initial score of 13. Despite a rapid clinical improvement after medical evacuation, he continued to show multifocal radiographic evidence of disease in all the lung quadrants on day 1 (score of 11) and day 2 (score of 5). Patient 2’s radiographs showed less severe disease at presentation (score of 6). Despite the need for continued treatment, his radiographs showed a rapid improvement, with radiographic score decreasing to 3 on day 1 and 1 on day 3. Conclusion The chest radiographs showed serial improvement after medical evacuation in both patients. There was not a strong correlation between clinical symptoms and radiographic severity in subsequent images.

Assessing personal exposure to environmental toxicants is a critical challenge for predicting disease risk. Previously, using human serum albumin (HSA)-based biomonitoring, we reported dosimetric relationships between adducts at HSA Cys 34 and ambient air pollutant levels (Smith et al., Chem. Res. Toxicol. 2021, 34, 1183. These results provided the foundation to explore modifications at other sites in HSA to reveal novel adducts of complex exposures. Thus, the Pan-Protein Adductomics (PPA) technology reported here is the next step toward an unbiased, comprehensive characterization of the HSA adductome. The PPA workflow requires <2 μL serum/plasma and uses nanoflow-liquid chromatography, gas-phase fractionation, and overlapping-window data-independent acquisition high-resolution tandem mass spectrometry. PPA analysis of albumin from nonsmoking women exposed to high levels of air pollution uncovered 68 unique locationspecific modifications (LSMs) across 21 HSA residues. While nearly half were located at Cys 34 (33 LSMs), 35 were detected on other residues, including Lys, His, Tyr, Ser, Met, and Arg. HSA adduct relative abundances spanned a ∼400 000-fold range and included putative products of exogenous (SO 2 , benzene, phycoerythrobilin) and endogenous (oxidation, lipid peroxidation, glycation, carbamylation) origin, as well as 24 modifications without annotations. PPA quantification revealed statistically significant changes in LSM levels across the 84 days of monitoring (∼3 HSA lifetimes) in the following putative adducts: Cys 34 trioxidation, βmethylthiolation, benzaldehyde, and benzene diol epoxide; Met 329 oxidation; Arg 145 dioxidation; and unannotated Cys 34 and His 146 adducts. Notably, the PPA workflow can be extended to any protein. Pan-Protein Adductomics is a novel and powerful strategy for untargeted global exploration of protein modifications.